What factors affect pulse oximetry?

Recommendations for Health Care Providers Be aware that multiple factors can affect the accuracy of a pulse oximeter reading, such as poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and use of fingernail polish.

What is the physical principle of a working pulse oximeter?

Pulse oximetry is based on two physical principles: (a) the presenceof a pulsatile signal generated by arterial blood, which is relativelyindependent of non-pulsatile arterial blood, venous and capillary blood, andother tissues; and (b) the fact that oxyhemoglobin (O2Hb) andreduced hemoglobin (Hb) have different …

How does light affect pulse oximetry?

Pulse oximeter readings are not significantly affected by 5 light sources commonly found in the clinical set- ting. Therefore, our data suggest that ambient light in the clinical setting has no clinically important effect on pulse oximetry readings.

Does bright light affect pulse oximetry?

External influences – Because the pulse oximeter measures the amount of light transmitted through arterial blood, bright light that shines directly on the sensor, whether artificial or natural, may affect readings.

What conditions can cause an inaccurate pulse oximetry reading?

Several factors can affect the accuracy of pulse oximeters, including poor circulation, skin temperature, skin thickness, current tobacco use, use of fingernail polish, and dark skin pigmentation, the FDA said. Recent reports have found that Black patients may not receive accurate readings from some oximeters.

Which light is used in pulse oximeter?

Modern pulse oximeters measure the amount of red and infrared light in an area of pulsatile blood flow. Because red light is primarily absorbed by deoxygenated blood and infrared light is primarily absorbed by oxygenated blood, the ratio of absorption can be measured.

Does presence or absence of light have any effect on the result of pulse oximeter reading?

2 Pulse oximetry readings are not significantly affected by light sources commonly used in clinical settings and ambient light in clinical setting has no clinically importance on pulse oximetry readings. 9 There have been a few studies regarding the effect of nail polish on pulse oximetry.

What effect can patient movement have on pulse oximetry procedure?

Patient movement can cause pulsatile venous flow to be incorrectly measured as arterial pulsations, thus producing an inaccurate oximetry and pulse-rate reading.

What can cause a false low reading on an oxygen saturation monitor?

Factors that can produce falsely low estimates of arterial hemoglobin saturation by pulse oximetry (SaO 2) include the presence of methemoglobin (1) anemia combined with hypotension (2,3) motion (4), dark skin pigmentation including certain skin dyes (5), blue or green fingernail polish (6), and severe tricuspid …

What are the limitations to the use of pulse oximeters compared to CO Oximeter?

Disadvantages of pulse oximetry include that it cannot be used to assess oxygen delivery (anemia) or adequacy of ventilation (PaCO2) and that accuracy is lessened in the presence of elevated dysfunctional hemoglobin levels (CoHb, metHb), with a tendency to overestimate SaO2 by an average of 2-3\%.

Is pulse oximetry a reliable indicator of ventilation?

A pulse oximeter gives no indication of a patient’s ventilation, only of the oxygenation status, and, thus, can give a false sense of security related to ventilation status with the administration of supplemental oxygen.